Known and in clinical use for many years, dental implants are metal fixtures that, when placed in the jawbone, function as “roots” for replacement teeth. Metal alloys, including for example, titanium alloys such as Ti-6Al-4V and Ti—Al-2.5Fe, Co—Cr—Mo, etc., are known biocompatible materials commonly employed for dental implants. Implants have also been used successfully in various bone implantation procedures including, but not limited to, spinal, hip, and knee procedures, as well as various limb salvage and anchoring operations.
It is known that the surface roughening of metallic implants, by mechanical or chemical processes, increases their in situ fixation by providing a greater surface area for osseointegration. However, some commonly employed roughening methods, including glass beading and grit blasting, leave embedded roughening media in the surface of the implant. There is mounting evidence that these embedded media contribute to eventual osteolysis, that is, bone readsorption.
Alternatively, it is known to provide implants with a porous surface coating, the presence of the pores providing an increased surface area or bone ingrowth into the implant. Such coatings include those achieved by sintering metal particles to the surface of a selected metallic implant at a density sufficient to leave numerous pores in the coating, and high-temperature sprayed metallic coatings, according to which metal particles are heated and thereafter deposited on the surface of the implant by high-speed bombardment.
Though titanium is a biocompatible metal, osseointegration around titanium is known to be inferior to that around bioactive ceramics, such as calcium phosphate. Accordingly, it is known to provide titanium dental implants with a coating of calcium phosphate, including, for example, hydroxyapatite (Ca10(PO4)6(OH)2). However, apatite-coated metal implants are also attended by drawbacks, including fracturing and, in some instances, bacterial colonization.
There thus continues to exist a need for metallic bone implants with improved implantability and methods for effectively making the same.